.308 stringing questions

[Silverboolit]

Just back from the range with a problem. Horizontal stringing with load. I am thinking not a load problem, but a mechanical one. Anyone with any ideas to share?
Load: 175 gr sized .310, AL gascheck
21 gr 2400, LRP, COAL 2.76"

[1950Hudson]

Check stock screws and scope/sight mounting screws?

[Doc Highwall]

What kind of rifle is it, bolt with a one piece stock or semi auto / pump with a two piece stock? What did you use for a bench set up a real bench rest or a sand bag?


Any information or better yet a picture that says a thousand words will help out.

[Silverboolit]

I am sorry..Howa 1500, glass bedded, concrete shooting bench , sandbag rests both front and rear. Scope rings have been aligned and honed. Tasco varmit/target scope (has always been good). Stock screws at 60 in lbs., scope and rings at 30 in lbs.

[country gent]

This is a light sporter barrel correct? WHat was the rate of fire? ( How fast) Could it be barrel heating up and moving away from the stock or a pressure point? Alot of things can cause this to happen, stresses heat, fouling, even light and wind.

[Silverboolit]

Heavy varmint barrel. Barrel did get warm, but not hot. Free floating barrel.

[Silverboolit]

Here are some of my groups before today:

[starnbar]

Check your recoil pad and the mounting screws

[tomme boy]

Head position or a bad scope if it is a proven scope. I had one of these scopes and I got rid of it fast because of how you had to have your eye looking into the scope. It was very critical to have it perfect.

[Larry Gibson]

Back the 2400 load off to 17, 18 & 19 gr and use a 3/4 gr Dacron filler.

Your previous 5 shot group may have been misleading you. The 15 shot group wasn't.

Larry Gibson

[Psypher]

If the load was not changed then rule out the human first. The recent group looks distinctly like breathing and hand squeeze.

If handgun round placement varies with velocity you might want to chrono some of those.

I'm wagering that Tasco is a culprit unless it's an old dog. Tasco made some kick butt scopes way back in the day.

[Silverboolit]

New Nikon Prostaff mounted and ready for the range. Upon closer examination, the windage knob on the Tasco is rough and can move by itself. Too bad, I kinda liked the scope. Off for the warranty. Will get to the range when the weather clears a little. Good excuse to upgrade to a better product, I hope.

Thanks to all for their suggestions, this forum is the best!!

[Silverboolit]

Beautiful day at the range. 5 shot target is 17 gr. of 2400, no filler. Other target is 15 rounds of 13 gr. Red Dot. All shot at 50 yds. Both shot well and no leading at all.

[pulaski]

It appears like your bullets are tipping (darker on top than on bottom , of holes ) .
Is there a rear sling mount on your rifle ? If it is contacting the bag on recoil you can get this type of stringing .
Thanks , Steve

[Silverboolit]

Target holder is not plumb, kinda tips a little. Will know al lot more when I get to 100 yds. I was surprised at the Red Dot load. Wish that I had a chrono to check velocities with. My guess is probably 14oo fps or so. Still, for killing paper, it seems to work pretty well. Just need more range time and practice!!!

[725]

When presented with a horizontal string problem, (after making sure the basics are correct -tight screws, rings, etc.,) I vary the seating depth ever so slightly. Keep good records. Have gone from touching the rifling, 10 thou off, 20 thou off, 30 thou off, and so on. Verticle strings, I vary the powder amounts - same way. Has worked for me. YMMV

[Petrol & Powder]

Throw that Tasco away and get a real scope.

[Petrol & Powder]

This came up in another thread and it's worth repeating: When dealing with optics, you generally get what you pay for.

I hate to spend money and I'm not keen on buying a name but quality optics are expensive to produce. You don't have to spend an enormous amount of money to obtain an adequate scope but it is almost impossible to obtain a decent scope without spending some money.
In the field of optics, everything is a compromise! Magnification / field of view / eye relief / weight / precision / loss of light / repeatability and COST !

You can get a good scope or you can get a cheap scope but I've Never seen a Good, Cheap scope.

[Silverboolit]

Is a Nikon Prostaff OK? Seems to be a good upgrade from the Tasco.

[Larry Gibson]

Silverboolit

Looks like you are on the way to solving the problem. When you test at 100 yards be consistent in loading the cartridges into the rifle so the powder is positioned close to the same. The 2400 will do better over the long run with a Dacron filler as it pre positions the powder consistently regardless of loading or rifle handling technique. No filler is recommended with the Red Dot load.

Don't chase too many things at once or you'll be chasing your tail in circles. One does get what one pays for with optics. I've several Tasco scopes. some have provided excellent service over many years and are quite reliable and useful. A couple others are TU and sit on a shelf as a reminder. If your Tasco varmint scope is a "World Class" model it should be a good serviceable scope. I have two "World Class" Tasco's and they have given excellent service for many years.

If those flyers are really flyers with the RD and 17/2400 loads then a bit better bullet sorting, alloy or casting will probably get rid of those also.

Larry Gibson